Hay and foraging equipment are utilized in the processing of plant material and include mowers, conditioners, flail choppers, windrowers, and balers for both dry and silage uses. The hay system, such as a square baler, includes a pickup mechanism, which picks crop material from the ground and supplies it to a bale-forming chamber. The bale-forming chamber receives the crop material and includes a plunger or piston that applies an axial force against an accumulation of the crop material to form a substantially square-shaped bale. The plunger or piston can further apply a force to a face of the bale to further densify the bale. Once the bale reaches a certain or desired density, the bale may be pushed and extruded out the rear of the baler.
Large square balers, round balers, and feeder wagons often include a pre-cutter feed-system to preprocess the crop to cut it to a shorter length before the bale formation to aid in mixing the crop into feed rations. The shorter length of crop is easier to mix compared longer length crop.
The pre-cutter feed-system comprises of a series of knives mounted to a structure, normally called the floor. It is common for these knives to be mounted in such a way that they can be lowered to bale with the knives lowered, if it is desired to not cut the crop. It is also common for the knives to be easily removed for service or replacement. It is further common for these knives to be protected with some sort of knife protection system to avoid knife damage if a foreign object is encountered such as a rock or metal object. This knife protection system allows the knife to lower when the foreign object is encountered. In these systems, the knife can be configured to automatically raise to resume operation with no operator input.
The majority of manufacturer's pre-cutter knife systems employ a knife engagement method to engage (raise) or disengage (lower) the knives which comprises of a roller that is forced against a surface of the knife. In this method, the roller pushes against a ramp or cam shape to push the knife through or above the floor surface. The knife travels upwardly until the roller enters into a depression or notch in the knife that holds the knife in the raised position. The notch is configured such that a relatively high force is necessary to move the spring loaded roller out of the notch to allow the knife to lower in the case of hitting a foreign object. To lower the knives manually, a mechanism pulls the roller out of the notch and away from the ramp-shaped profile of the knife allowing either gravity to lower the knife, or subsequent crop fed into the feed-system can push the knives down.
A common issue faced with pre-cutter knife systems is that the knives become stuck in place. A stuck knife is a problem, because freeing up the knife requires manual intervention and often requires the use of a tool to free the knife. Additionally, the end user becomes frustrated when discovering that one or more knives were not raised and previously harvested hay has not been cut.
A stuck knife results when exposed to many different types of conditions including: (1) a knife that is forced down from a foreign object during knife protection that does not automatically raise; (2) the knives are lowered to bale without cutting, and when knives are raised to resume cutting the knives do not raise; (3) the knives are lowered to unplug the rotor from the cab and when knives are raised to resume cutting the knives do not raise. Reasons for knives not raising include: (1) crop buildup between the knives and the slots in the floor that the knife passes through; and (2) crop buildup under the floor structure in the knife area that adds resistance to the knife and increases the required force to raise one or more knives. Some manufacturers have systems in which the knife system frame is mounted above the rotor. In these types of systems, similar problematic conditions occur.
Other problems result from the crop material being bunched at one place or otherwise non-uniformly distributed across the knives, which causes surges in the amount of power required to process the material encountered. If the material encountered is too thick or even includes some foreign material such as a piece of wood or a stone, a plug can be formed that causes the baling mechanism to be overloaded. In some machines, this requires operator intervention requiring the operator to stop the tractor to make an attempt to unplug the congested material by reversing the travel of the tractor to try to pull some of the material out. The presence of a plug often requires the operator to stop the drive mechanism and then release various aspects of the baler mechanism associated with the flow of the material so that the plug can be removed either manually or by operating portions of the baler with mechanisms in their non-normal operating positions to try to clear the plug from the baler. Once the plug is removed, the operator repositions the mechanisms that were disengaged, moving them back into a normal operating position. These conventional techniques require at least some limited operator intervention which can potentially damage the machine by operating it with only some of the mechanisms being moved to a released position.
In other aspects, various unplugging devices are included in the feeding systems on hay and forage equipment which include drop floors, knife disengagement, reversers, rotor movement, pickup baffle positioners, power feed clutches, and the like. These devices are activated electrically, hydraulically, PTO driven, or a combination thereof. These devices are activated individually to make the necessary steps to relieve tight plugs and to then sequentially feed crops through the feeding device. Actuating these devices individually is cumbersome, time-consuming and difficult to understand for inexperienced operators.